Synthesis and characterization of chiral ruthenium(II) complexes Λ/Δ-[Ru(bpy)2(H2iip)](ClO4)2 as stabilizers of c-myc G-quadruplex DNA

Abstract

In this article, two chiral ruthenium(II) complexes, Λ/Δ-[Ru(bpy)2(H2iip)](ClO4)2 (Λ-1 and Δ-1, bpy = 2,2-bipyridine; H2iip = 2-(indol-3-yl)-imidazo[4,5f][1, 10]phenanthroline), were synthesized and investigated as c-myc G4 DNA stabilizers. The interaction of both complexes with c-myc G4 DNA has been studied using UV–vis spectra, CD spectra, and ITC experiments, and the results show that both isomers strongly bind with c-myc G4 DNA. Furthermore, the FRET melting point experiments give a ΔTm for Λ-1 and Δ-1, which is about 9.5 and 8.3 °C, respectively, indicating that both isomers can stabilize the G-quadruplex conformation of c-myc oncogene in vitro. As a result, the replication ability of c-myc DNA, as evaluated by using PCR-stop assay, by both isomers. Besides, the inhibitory activity evaluated by MTT assay showed that Λ-1 and Δ-1 can inhibit the growth of MDA-MB-231 cells, suggesting their potential utility as inhibitors targeting to c-myc G-quadruplexe in chemotherapy.